MATHLIBANNEX / EXACT SOURCE

MathlibAnnex.CStarAlgebra.CAR.exists_targetDefectVectorFamily

Exact source: MathlibAnnex/Analysis/CStarAlgebra/CAR/CaptureSurviving.lean, lines 176–250.

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1import MathlibAnnex.Analysis.CStarAlgebra.CAR.CaptureZero
2import Mathlib.Analysis.Normed.Module.Normalize
3
4/-!
5# Vectors carried by a surviving completed-CAR defect
6
7The target-side unitary-completion relation transports a normalized vector
8from a nonzero initial limiting fixed space to the root limiting fixed space.
9The actual completed-CAR compression estimates then identify both vector
10states.  No ambient rank-one assertion is made for an arbitrary target
11representation.
12-/
13
14set_option autoImplicit false
15set_option maxHeartbeats 1200000
16
17noncomputable section
18
19open Filter Topology
20open scoped ComplexOrder ENNReal lp InnerProduct
21
22namespace MathlibAnnex.CStarAlgebra.CAR
23
24open MathlibAnnex.Analysis.CStarAlgebra
25open MathlibAnnex.Analysis.InnerProductSpace
26
27universe v
28
29/-- A specified nonzero limiting fixed space supplies unit vectors carrying
30the selected state and the root state, joined by the represented target
31generator. -/
32theorem exists_targetDefectVectors_of_fixedSpace_ne_bot
33    (family : RepresentativeShellFamily)
34    (L : MathlibAnnex.CStarAlgebra.PureState.GNSClass Limit →
35      MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState →L[ℂ]
36        MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState)
37    (hLunit : ∀ i, L i ∈ unitary
38      (MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState →L[ℂ]
39        MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState))
40    (hLsource : ∀ i n, (L i).comp (selectedAtomicRepresentation
41      (transportedFlag family i n - transportedFlag family i (n + 1))) =
42        representedShellLink family i n)
43    {K : Type v} [NormedAddCommGroup K] [InnerProductSpace ℂ K]
44    [CompleteSpace K] (rho : Representation (AtomicTarget L) K)
45    (i : MathlibAnnex.CStarAlgebra.PureState.GNSClass Limit)
46    (hi : (⨅ n, ((restrictedRepresentation L rho)
47      (transportedFlag family i n)).range) ≠ ⊥) :
48    ∃ eta_i eta_o : K,
49      ‖eta_i‖ = 1 ∧ ‖eta_o‖ = 1 ∧
50      (∀ n, (restrictedRepresentation L rho)
51        (transportedFlag family i n) eta_i = eta_i) ∧
52      (∀ n, (restrictedRepresentation L rho) (rootFlag n) eta_o = eta_o) ∧
53      (Unitary.linearIsometryEquiv
54        (representedGeneratorUnitary L hLunit rho i) : K ≃ₗᵢ[ℂ] K) eta_i = eta_o ∧
55      Representation.vectorFunctional (restrictedRepresentation L rho) eta_i =
56        (MathlibAnnex.CStarAlgebra.PureState.representative completedRootPureState i).1 ∧
57      Representation.vectorFunctional (restrictedRepresentation L rho) eta_o =
58        rootState := by
59  let sigma := restrictedRepresentation L rho
60  let U : ℕ → Submodule ℂ K := fun n ↦
61    (sigma (transportedFlag family i n)).range
62  let V : ℕ → Submodule ℂ K := fun n ↦ (sigma (rootFlag n)).range
63  obtain ⟨S, T, P, Q, R, -, -, -, -, -, -, hPrange, -, hQrange, -, -, -, -,
64      -, -, -, htransport⟩ :=
65    exists_targetShellReconstruction family L hLunit hLsource rho i
66  have hU_ne : (⨅ n, U n) ≠ ⊥ := by
67    simpa [U, sigma] using hi
68  obtain ⟨x, hxU, hxne⟩ := Submodule.exists_mem_ne_zero_of_ne_bot hU_ne
69  let eta_i : K := NormedSpace.normalize x
70  have heta_i_norm : ‖eta_i‖ = 1 := NormedSpace.norm_normalize hxne
71  have heta_i_mem : eta_i ∈ ⨅ n, U n := by
72    change NormedSpace.normalize x ∈ ⨅ n, U n
73    rw [NormedSpace.normalize]
74    exact (⨅ n, U n).smul_mem (‖x‖⁻¹ : ℝ) hxU
75  let e : K ≃ₗᵢ[ℂ] K := Unitary.linearIsometryEquiv
76    (representedGeneratorUnitary L hLunit rho i)
77  let eta_o : K := e eta_i
78  have heta_o_norm : ‖eta_o‖ = 1 := by
79    rw [show ‖eta_o‖ = ‖eta_i‖ by exact e.norm_map eta_i]
80    exact heta_i_norm
81  have heta_o_mem : eta_o ∈ ⨅ n, V n := by
82    exact (htransport eta_i).1 heta_i_mem
83  have heta_i_fixed (n : ℕ) :
84      sigma (transportedFlag family i n) eta_i = eta_i := by
85    have hn : eta_i ∈ U n := (Submodule.mem_iInf U).mp heta_i_mem n
86    exact LinearMap.IsIdempotentElem.mem_range_iff
87      (ContinuousLinearMap.IsIdempotentElem.toLinearMap
88        (IsStarProjection.map_representation sigma
89          (isStarProjection_transportedFlag family i n)).isIdempotentElem) |>.mp hn
90  have heta_o_fixed (n : ℕ) : sigma (rootFlag n) eta_o = eta_o := by
91    have hn : eta_o ∈ V n := (Submodule.mem_iInf V).mp heta_o_mem n
92    exact LinearMap.IsIdempotentElem.mem_range_iff
93      (ContinuousLinearMap.IsIdempotentElem.toLinearMap
94        (IsStarProjection.map_representation sigma
95          (isStarProjection_rootFlag n)).isIdempotentElem) |>.mp hn
96  have heta_i_state : Representation.vectorFunctional sigma eta_i =
97      (MathlibAnnex.CStarAlgebra.PureState.representative completedRootPureState i).1 := by
98    apply ContinuousLinearMap.ext
99    intro b
100    have hcoeff := inner_map_eq_of_compression_tendsto sigma
101      (Representation.continuousLinearMap sigma).continuous
102      (transportedFlag family i)
103      (MathlibAnnex.CStarAlgebra.PureState.representative completedRootPureState i).1 b eta_i eta_i
104      (fun n ↦ (isStarProjection_transportedFlag family i n).isSelfAdjoint.star_eq)
105      heta_i_fixed heta_i_fixed
106      (tendsto_representative_transported_compression family i b)
107    have hself : inner ℂ eta_i eta_i = 1 := by
108      rw [inner_self_eq_norm_sq_to_K, heta_i_norm]
109      norm_num
110    change inner ℂ eta_i (sigma b eta_i) =
111      (MathlibAnnex.CStarAlgebra.PureState.representative completedRootPureState i).1 b
112    calc
113      inner ℂ eta_i (sigma b eta_i) =
114          (MathlibAnnex.CStarAlgebra.PureState.representative completedRootPureState i).1 b *
115            inner ℂ eta_i eta_i := hcoeff
116      _ = (MathlibAnnex.CStarAlgebra.PureState.representative completedRootPureState i).1 b := by
117        rw [hself, mul_one]
118  have heta_o_state : Representation.vectorFunctional sigma eta_o = rootState := by
119    apply ContinuousLinearMap.ext
120    intro b
121    have hcompression : Tendsto
122        (fun n ↦ rootFlag n * b * rootFlag n - rootState b • rootFlag n)
123        atTop (nhds 0) := by
124      simpa using tendsto_transported_compressionError
125        (StarAlgEquiv.refl ℂ Limit) rootState (fun _ ↦ rfl) b
126    have hcoeff := inner_map_eq_of_compression_tendsto sigma
127      (Representation.continuousLinearMap sigma).continuous rootFlag rootState
128      b eta_o eta_o
129      (fun n ↦ (isStarProjection_rootFlag n).isSelfAdjoint.star_eq)
130      heta_o_fixed heta_o_fixed hcompression
131    have hself : inner ℂ eta_o eta_o = 1 := by
132      rw [inner_self_eq_norm_sq_to_K, heta_o_norm]
133      norm_num
134    change inner ℂ eta_o (sigma b eta_o) = rootState b
135    calc
136      inner ℂ eta_o (sigma b eta_o) =
137          rootState b * inner ℂ eta_o eta_o := hcoeff
138      _ = rootState b := by rw [hself, mul_one]
139  exact ⟨eta_i, eta_o, heta_i_norm, heta_o_norm,
140    heta_i_fixed, heta_o_fixed, rfl, heta_i_state, heta_o_state⟩
141
142/-- Every irreducible target representation contains a transported pair of
143unit defect vectors with the exact selected and root completed-CAR states. -/
144theorem exists_targetDefectVectors
145    (family : RepresentativeShellFamily)
146    (L : MathlibAnnex.CStarAlgebra.PureState.GNSClass Limit →
147      MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState →L[ℂ]
148        MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState)
149    (hLunit : ∀ i, L i ∈ unitary
150      (MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState →L[ℂ]
151        MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState))
152    (hLsource : ∀ i n, (L i).comp (selectedAtomicRepresentation
153      (transportedFlag family i n - transportedFlag family i (n + 1))) =
154        representedShellLink family i n)
155    {K : Type v} [NormedAddCommGroup K] [InnerProductSpace ℂ K]
156    [CompleteSpace K] (rho : Representation (AtomicTarget L) K)
157    (hrho : rho.IsIrreducible) :
158    ∃ (i : MathlibAnnex.CStarAlgebra.PureState.GNSClass Limit) (eta_i eta_o : K),
159      ‖eta_i‖ = 1 ∧ ‖eta_o‖ = 1 ∧
160      (∀ n, (restrictedRepresentation L rho)
161        (transportedFlag family i n) eta_i = eta_i) ∧
162      (∀ n, (restrictedRepresentation L rho) (rootFlag n) eta_o = eta_o) ∧
163      (Unitary.linearIsometryEquiv
164        (representedGeneratorUnitary L hLunit rho i) : K ≃ₗᵢ[ℂ] K) eta_i = eta_o ∧
165      Representation.vectorFunctional (restrictedRepresentation L rho) eta_i =
166        (MathlibAnnex.CStarAlgebra.PureState.representative completedRootPureState i).1 ∧
167      Representation.vectorFunctional (restrictedRepresentation L rho) eta_o =
168        rootState := by
169  obtain ⟨i, hi⟩ := exists_nonzero_targetFixedSpace
170    family L hLunit hLsource rho hrho
171  obtain ⟨eta_i, eta_o, h⟩ :=
172    exists_targetDefectVectors_of_fixedSpace_ne_bot
173      family L hLunit hLsource rho i hi
174  exact ⟨i, eta_i, eta_o, h⟩
175
176/-- A surviving defect yields one common root unit vector and a compatible
177unit defect vector for every selected pure-state class.  Each represented
178generator sends its selected vector to the same root vector, and every vector
179state is identified from the actual completed-CAR compression theorem. -/
180theorem exists_targetDefectVectorFamily
181    (family : RepresentativeShellFamily)
182    (L : MathlibAnnex.CStarAlgebra.PureState.GNSClass Limit →
183      MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState →L[ℂ]
184        MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState)
185    (hLunit : ∀ i, L i ∈ unitary
186      (MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState →L[ℂ]
187        MathlibAnnex.CStarAlgebra.PureState.SelectedAtomicHilbert completedRootPureState))
188    (hLsource : ∀ i n, (L i).comp (selectedAtomicRepresentation
189      (transportedFlag family i n - transportedFlag family i (n + 1))) =
190        representedShellLink family i n)
191    {K : Type v} [NormedAddCommGroup K] [InnerProductSpace ℂ K]
192    [CompleteSpace K] (rho : Representation (AtomicTarget L) K)
193    (hrho : rho.IsIrreducible) :
194    ∃ (eta_o : K) (eta : MathlibAnnex.CStarAlgebra.PureState.GNSClass Limit → K),
195      ‖eta_o‖ = 1 ∧
196      (∀ n, (restrictedRepresentation L rho) (rootFlag n) eta_o = eta_o) ∧
197      Representation.vectorFunctional (restrictedRepresentation L rho) eta_o =
198        rootState ∧
199      ∀ i,
200        ‖eta i‖ = 1 ∧
201        (∀ n, (restrictedRepresentation L rho)
202          (transportedFlag family i n) (eta i) = eta i) ∧
203        (Unitary.linearIsometryEquiv
204          (representedGeneratorUnitary L hLunit rho i) : K ≃ₗᵢ[ℂ] K) (eta i) =
205            eta_o ∧
206        Representation.vectorFunctional (restrictedRepresentation L rho) (eta i) =
207          (MathlibAnnex.CStarAlgebra.PureState.representative completedRootPureState i).1 := by
208  obtain ⟨i₀, eta₀, eta_o, -, heta_o_norm, -, heta_o_fixed, -, -,
209      heta_o_state⟩ :=
210    exists_targetDefectVectors family L hLunit hLsource rho hrho
211  let sigma := restrictedRepresentation L rho
212  have heta_o_mem : eta_o ∈
213      (⨅ n, (sigma (rootFlag n)).range) := by
214    rw [Submodule.mem_iInf]
215    intro n
216    exact ⟨eta_o, heta_o_fixed n⟩
217  let e (i : MathlibAnnex.CStarAlgebra.PureState.GNSClass Limit) : K ≃ₗᵢ[ℂ] K :=
218    Unitary.linearIsometryEquiv
219      (representedGeneratorUnitary L hLunit rho i)
220  let eta (i : MathlibAnnex.CStarAlgebra.PureState.GNSClass Limit) : K := (e i).symm eta_o
221  refine ⟨eta_o, eta, heta_o_norm, heta_o_fixed, heta_o_state, ?_⟩
222  intro i
223  have heta_norm : ‖eta i‖ = 1 := by
224    rw [show ‖eta i‖ = ‖eta_o‖ by exact (e i).symm.norm_map eta_o]
225    exact heta_o_norm
226  obtain ⟨S, T, P, Q, R, -, -, -, -, -, -, -, -, -, -, -, -, -, -, -, -,
227      htransport⟩ :=
228    exists_targetShellReconstruction family L hLunit hLsource rho i
229  have heta_mem : eta i ∈
230      (⨅ n, (sigma (transportedFlag family i n)).range) := by
231    apply (htransport (eta i)).2
232    simpa [e, eta] using heta_o_mem
233  have heta_fixed (n : ℕ) :
234      sigma (transportedFlag family i n) (eta i) = eta i := by
235    have hn : eta i ∈ (sigma (transportedFlag family i n)).range :=
236      (Submodule.mem_iInf _).mp heta_mem n
237    exact LinearMap.IsIdempotentElem.mem_range_iff
238      (ContinuousLinearMap.IsIdempotentElem.toLinearMap
239        (IsStarProjection.map_representation sigma
240          (isStarProjection_transportedFlag family i n)).isIdempotentElem) |>.mp hn
241  have heta_state : Representation.vectorFunctional sigma (eta i) =
242      (MathlibAnnex.CStarAlgebra.PureState.representative completedRootPureState i).1 := by
243    apply vectorFunctional_eq_of_compression_tendsto sigma
244      (transportedFlag family i)
245      (MathlibAnnex.CStarAlgebra.PureState.representative completedRootPureState i).1
246      (fun n ↦ (isStarProjection_transportedFlag family i n).isSelfAdjoint.star_eq)
247      (tendsto_representative_transported_compression family i)
248      (eta i) heta_norm heta_fixed
249  refine ⟨heta_norm, heta_fixed, ?_, heta_state⟩
250  simp [e, eta]
251
252end MathlibAnnex.CStarAlgebra.CAR
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